Metachronous gonadal and extragonadal primaries, or late relapse of germ cell tumor?

We report five distinct cases of apparently metachronous extragonadal and gonadal germ cell tumors (GCT) occurring in the same patient. Two patients had metachronous GCT of the central nervous system and the testis. One of these patients had been successfully treated for a germinoma of the pineal gland and developed a nonseminomatous GCT of the testis 10 years later. The second patient had a primary seminoma of the testis treated by orchiectomy followed by radiotherapy and developed a germinoma of the sphenoidal sinus 17 months later. Three other patients had an apparently metachronous retroperitoneal and testicular GCT with 22, 44, and 66 months elapsing, respectively, between the first and second neoplasms. These cases suggest that the remaining testis is not only at risk for a second primary GCT, but that a second GCT may emerge at an extragonadal site. A genetic predisposition may account for some of these cases and the occurrence of bilateral testicular GCT. In none of these cases, however, could we ascertain whether testicular GCT was truly a second primary or a relapse of a 'primary' retroperitoneal GCT in our cases.